"We were not strong enough to kill the game," Mourinho said. "They [West Brom] had a reaction and we couldn't cope.

"It was down to the attacking players stopping to play; my defensive line playing too deep. We gave them the ball and were waiting for them to put it in the box. That's not our game.

"A little bit of a lack of personality, perhaps. We must have the personality to get out of our half, to not accept that pressure or to play that long in the last third of the pitch. So a bit of everything."

"It was not very different to the game against City [won 1-0 at the Etihad Stadium last week] ... but in that game we didn't make one defensive mistake, even when they put pressure on us.

"Today it [the pressure] was not for five minutes. It was 20 minutes and we made a couple of defensive mistakes. We have to kill games and, when we don't kill, we can't make defensive mistakes."

John Terry missed the game through injury and, asked whether the defender's presence would have made the difference, Mourinho said: "John's a guy with big personality so it might have been different with him, yes. But I'd prefer to say we didn't kill the game. We accepted for too long their dominance in the last 20 minutes and we were punished for our mistakes."